The psoas muscle group is a deep, central structure linking the spine and the lower body. It is composed of the psoas major and the psoas minor, often grouped with the iliacus muscle to form the iliopsoas complex. The psoas major originates from the twelfth thoracic vertebra (T12) down to the fifth lumbar vertebra (L5). It travels through the pelvis to insert on the femur, making it the only muscle that directly connects the torso to the legs. This position establishes the psoas as a major deep core muscle, influencing both spinal stability and hip movement.
Understanding Psoas Function
The primary function of the psoas is hip flexion, which involves lifting the knee toward the chest or bending forward at the waist. This action is integral to everyday motions like walking, running, and climbing stairs. The psoas major also plays a significant role in stabilizing the lumbar spine and maintaining upright posture. It helps control the anterior tilt of the pelvis and stabilizes the trunk during sitting and dynamic activities. When the psoas is weak, other muscles may compensate, leading to muscular imbalances and discomfort. Prolonged sitting often results in a shortened and weak psoas, stressing the lumbar spine. Targeted strengthening restores the muscle’s capacity to stabilize the spine and powerfully flex the hip.
Foundational Strengthening Exercises
Strengthening the psoas should begin with low-load movements emphasizing isolation and control. These foundational exercises focus on maintaining a neutral lumbar spine throughout the range of motion, preventing compensation from larger muscles.
Supine Marching
The Supine Marching exercise is performed lying on your back with knees bent and feet flat. Slowly lift one knee toward the chest, aiming for a 90-degree bend at the hip. Ensure the lower back remains pressed gently into the floor without arching. Controlled lowering of the leg is important, as it builds eccentric strength. Repeat 10 to 15 repetitions per side, focusing on slow, deliberate movement.
Controlled Straight Leg Raise
The Controlled Straight Leg Raise challenges the muscle using a greater lever arm. Lie flat on your back with one leg straight and the other knee bent for stability. Slowly lift the straight leg only a few inches off the floor. Stop the movement just before the pelvis begins to tilt or the lower back lifts away from the floor. This small range of motion requires the psoas to work hard to maintain spinal stability while initiating hip flexion.
Standing Hip Flexion
The Standing Hip Flexion introduces the psoas to its functional role against gravity. While standing upright, slowly lift one knee toward the chest until the thigh is parallel to the floor. Avoid leaning back or laterally tilting the torso, which indicates compensation. Hold the top position for two to three seconds before slowly lowering the foot back to the ground with control.
Advanced Progression and Dynamic Strengthening
Once foundational control is established, exercises can be progressed by introducing external resistance, dynamic movement, or greater stability demands. These advanced techniques integrate psoas strength with the rest of the core for improved athletic performance.
Front Support Hip Flexion with Resistance
This exercise increases load while demanding significant core stability. Start in a plank position with a resistance band looped around one foot and anchored behind you. Maintain a rigid plank posture without raising the hips. Drive the knee of the banded leg toward the chest against the resistance. This simultaneously strengthens the psoas and trains the abdominal muscles to resist spinal extension.
Alternating Leg Raises
Alternating Leg Raises provide an advanced challenge, integrating grip strength and abdominal endurance with hip flexor power. They are often performed while hanging from a pull-up bar, lifting both knees toward the chest. If hanging is too difficult, performing the movement supine on the floor requires the psoas to lift the full weight of the legs against gravity. When performing this exercise, prevent the lower back from arching or separating from the floor as the legs descend.
Dynamic Movements
Dynamic movements, such as High Knee Runs or Mountain Climbers, translate isolated strength into functional speed and power. Mountain Climbers, performed in a plank position, require rapid, alternating hip flexion to drive the knees toward the chest. The psoas must fire quickly to lift the legs while the core stabilizes the trunk against the alternating motion. This dynamic work helps build the speed and explosiveness necessary for running and jumping.
Integrating Psoas Work into a Routine
Psoas strengthening should be incorporated into a training schedule two to three times per week, allowing for adequate rest and recovery. For most exercises, aim for three sets of six to twelve repetitions, or hold isometric positions for five to ten seconds. Select a resistance or leverage that causes momentary muscle fatigue by the final repetitions. Consistency in form is paramount, especially maintaining a neutral pelvic tilt to ensure the muscle is working effectively. If the exercise causes sharp pain in the lower back or groin, stop immediately and reduce the range of motion or load. Progress the exercises gradually by adding sets, increasing hold time, or introducing stronger resistance. Individuals with pre-existing back or hip discomfort should consult a physical therapist before starting a new strengthening routine.